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Abstract:

A method for transmitting, by a user equipment (UE), a channel state
information (CSI) in a wireless communication system is disclosed. The
method includes receiving control information about a transmission of the
CSI from a serving eNodeB, allocating a CSI combination composed of
different CSIs to one subframe based on the received control information,
and transmitting the CSI combination to the serving eNodeB in the
allocated subframe, wherein the control information includes information
on a maximum payload size of a CSI being able to be transmitted in one
subframe, a transmission period and a transmission start time point of
the CSI combination, and a transmission period and a transmission start
time point of each of the different CSIs.

Claims:

1. A method for transmitting, by a user equipment (UE), a channel state
information (CSI) in a wireless communication system, the method
comprising: receiving control information about a transmission of the CSI
from a serving eNodeB; allocating a CSI combination composed of different
CSIs to one subframe based on the received control information; and
transmitting the CSI combination to the serving eNodeB in the allocated
subframe, wherein the control information includes information on a
maximum payload size of a CSI being able to be transmitted in one
subframe, a transmission period and a transmission start time point of
the CSI combination, and a transmission period and a transmission start
time point of each of the different CSIs.

2. The method according to claim 1, wherein the transmission period of
the CSI combination or each of the different CSIs is set to a multiple of
a predetermined unit transmission period.

3. The method according to claim 1, wherein the allocating further
comprises: allocating an additional CSI to the subframe to which the CSI
combination has been allocated, wherein the additional CSI includes a CSI
between eNodeBs which perform downlink transmission to the UE.

4. The method according to claim 1, wherein the CSI combination comprises
at least two different CSIs.

5. The method according to claim 1, wherein, when at least two CSI
combinations are allocated to the one subframe and collide with each
other, the transmitting includes transmitting one CSI combination
selected from the at least two CSI combinations.

6. The method according to claim 5, wherein the selection is determined
according to a priority and the priority is given to each of the CSI
combinations or each of the different CSIs in the CSI combinations.

7. A user equipment (UE) for transmitting a channel state information
(CSI) in a wirless communication system, the UE comprising: a radio
frequency (RF) unit for transmitting or receiving a radio signal; and a
processor for controlling the RF unit, wherein the processor controls the
RF unit to receive control information about a transmission of the CSI
from a serving eNodeB, allocates a CSI combination composed of different
CSIs to one subframe based on the received control information, and
controls the RF unit to transmit the CSI combination to the serving
eNodeB in the allocated subframe, wherein the control information
includes information on a maximum payload size of a CSI being able to be
transmitted in one subframe, a transmission period and a transmission
start time point of the CSI combination, and a transmission period and a
transmission start time point of each of the different CSIs.

8. The UE according to claim 7, wherein the transmission period of the
CSI combination or each of the different CSIs is set to a multiple of a
predetermined unit transmission period.

9. The UE according to claim 7, wherein the processor allocates an
additional CSI to a subframe to which the CSI combination has been
allocated, wherein the additional CSI includes a CSI between eNodeBs that
perform downlink transmission to the UE.

10. The UE according to claim 7, wherein the processor allocates a CSI
combination composed of at least two different CSIs to the subframe.

11. The UE according to claim 7, wherein, when at least two CSI
combinations are allocated the one subframe and collide with each other,
the processor controls the RF unit to transmit one CSI combination
selected from the at least two CSI combinations.

12. The UE according to claim 11, wherein the selection is determined
according to a priority, and the priority is given to each of the CSI
combinations or each of the different CSIs in the CSI combinations.

13. A method for receiving, by an eNodeB, a channel state information
(CSI) in a wireless communication system, the method comprising:
transmitting control information on transmission of the CSI to a user
equipment (UE); and receiving, from the UE, a CSI combination in a
subframe to which the CSI combination has been allocated based on the
control information, wherein the CSI combination comprises different
CSIs, and wherein the control information includes information on a
maximum payload size of a CSI being able to be transmitted in one
subframe, a transmission period and a transmission start time point of
the CSI combination, and a transmission period and a transmission start
time point of each of the different CSIs.

14. The method according to claim 13, wherein the transmission period of
the CSI combination or each of the different CSIs is set to a multiple of
a predetermined unit transmission period.

15. The method according to claim 13, wherein the CSI combination
comprises at least two different CSIs.

16. An eNodeB for receiving a channel state information (CSI) in a
wireless communication system, the eNodeB comprising: a radio frequency
unit for transmitting and receiving a radio signal; and a processor for
controlling the RF unit, wherein the processor controls the RF unit to
transmit control information on transmission of the CSI to a user
equipment (UE) and to receive the CSI combination, from the UE, in a
subframe to which the CSI combination has been allocated based on the
control information, wherein the CSI combination comprises different
CSIs, wherein the control information includes information on a maximum
payload size of a CSI being able to be transmitted in one subframe, a
transmission period and a transmission start time point of the CSI
combination, and a transmission period and a transmission start time
point of each of the different CSIs.

17. The eNodeB according to claim 16, wherein the transmission period of
the CSI combination or each of the different CSIs is set to a multiple of
a predetermined unit transmission period.

18. The eNodeB according to claim 16, wherein the CSI combination
comprises at least two different CSIs.

Description:

[0001] This application claims the benefit of U.S. Patent Application No.
61/547,742, filed on Oct. 16, 2011, which is hereby incorporated by
reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to transmitting channel state
information (CSI), and more particularly, to a method and apparatus for
transmitting channel state information on a plurality of transmission
points in the downlink of a multiple cell wireless communication system.

[0004] 2. Discussion of the Related Art

[0005] Various devices such as smart phones, tablet PCs, tec., which
require machine-to-machine communication and the large amount of data
transmission, and such technologies are being introduced and distributed.
As such, the amount of data required to be processed in the cellular
network is rapidly increasing. Likewise, in order to satisfy the
requirement on the amount of data to be processed which is on a rapid
increase, a carrier aggregation technology, a cognitive radio technology,
etc. for efficiently utilizing more frequency bands, and a multiple
antenna technology, a multiple base station cooperation technology, etc.
for increasing the data capacity transmitted within the limited
frequency, are being developed.

[0006] Among such technologies, a coordinated multiple point transmission
and reception (CoMP) scheme has been suggested for improvement of
performance of a wireless communication system. It is expected that the
CoMP scheme would improve the performance of a user equipment (UE)
located in the cell boundary, and improve the average sector throughput.
However, even if the CoMP scheme is applied, there is still an inter-cell
interference (ICI) which reduces performance of the UE located in the
cell boundary, and this leads to an issue on channel assumption of a UE
which is provided communication services through the CoMP scheme.

SUMMARY OF THE INVENTION

[0007] An object of the present invention is to provide a transmission
structure for transmitting channel state information (CSI) on
transmission points (TPs) which participate in a coordinated multiple
point transmission (CoMP) scheme within limited time-frequency resources.

[0008] Additional advantages, objects, and features of the invention will
be set forth in part in the description which follows and in part will
become apparent to those having ordinary skill in the art upon
examination of the following or may be learned from practice of the
invention. The objectives and other advantages of the invention may be
realized and attained by the structure particularly pointed out in the
written description and claims hereof as well as the appended drawings.

[0009] To achieve these objects and other advantages and in accordance
with the purpose of the invention, as embodied and broadly described
herein, a method for transmitting, by a user equipment (UE), a channel
state information (CSI) in a wireless communication system includes
receiving control information about a transmission of the CSI from a
serving eNodeB, allocating a CSI combination comprised of different CSIs
to one subframe on the basis of the received control information, and
transmitting the CSI combination to the serving eNodeB in the allocated
subframe, wherein the control information includes information on a
maximum payload size of a CSI being able to be transmitted in one
subframe, a transmission period and a transmission start time point of
the CSI combination, and a transmission period and a transmission start
time point of each of the different CSIs.

[0010] Preferably, the transmission period of the CSI combination or each
of the different CSIs is set to a multiple of a predetermined unit
transmission period.

[0011] Preferably, the allocating further includes allocating an
additional CSI to the subframe to which the CSI combination has been
allocated, wherein the additional CSI includes a CSI between eNodeBs
which perform downlink transmission to the UE.

[0012] Preferably, the CSI combination comprises at least two different
CSIs.

[0013] Preferably, when at least two CSI combinations are allocated to the
one subframe and collide with each other, the transmitting includes
transmitting one CSI combination selected from the at least two CSI
combinations.

[0014] Preferably, the selection is determined according to a priority and
the priority is given to each of the CSI combinations or each of the
different CSIs in the CSI combinations.

[0015] In another aspect of the present invention, a user equipment (UE)
for transmitting a channel state information (CSI) in a wireless
communication system includes a radio frequency (RF) unit for
transmitting or receiving a radio signal, and a processor for controlling
the RF unit, wherein the processor controls the RF unit to receive
control information about a transmission of the CSI from the serving
eNodeB, allocates a CSI combination comprised of different CSIs to one
subframe based on the received control information, and controls the RF
unit to transmit the CSI combination to the serving eNodeB in the
allocated subframe, wherein the control information includes information
on a maximum payload size of a CSI being able to be transmitted in one
subframe, a transmission period and a transmission start time point of
the CSI combination, and a transmission period and a transmission start
time point of each of the different CSIs.

[0016] Preferably, the transmission period of the CSI combination or each
of the different CSIs is set to a multiple of a predetermined unit
transmission period.

[0017] Preferably, the processor allocates an additional CSI to a subframe
to which the CSI combination has been allocated, wherein the additional
CSI includes a CSI between eNodeBs that perform downlink transmission to
the UE.

[0018] Preferably, the processor allocates a CSI combination comprised of
at least two different CSIs to the subframe.

[0019] Preferably, when at least two CSI combinations are allocated the
one subframe and collide with each other, the processor controls the RF
unit to transmit one CSI combination selected from the at least two CSI
combinations.

[0020] Preferably, the selection is determined according to a priority,
and the priority is given to each of the CSI combinations or each of the
different CSIs in the CSI combinations.

[0021] In another aspect of the present invention, a method for receiving,
by an eNodeB, a channel state information (CSI) in a wireless
communication system includes transmitting control information on
transmission of the CSI to a user equipment (UE), and receiving a CSI
combination, from the UE, in a subframe to which the CSI combination has
been allocated based on the control information, wherein the CSI
combination comprises different CSIs, and wherein the control information
includes information on a maximum payload size of a CSI being able to be
transmitted in one subframe, a transmission period and a transmission
start time point of the CSI combination, and a transmission period and a
transmission start time point of each of the different CSIs.

[0022] Preferably, the transmission period of the CSI combination or each
of the different CSIs is set to a multiple of a predetermined unit
transmission period.

[0023] Preferably, the CSI combination comprises at least two different
CSIs.

[0024] In another aspect of the present invention, an eNodeB for receiving
a channel state information (CSI) in a wireless communication system
includes a radio frequency unit for transmitting and receiving a radio
signal, and a processor for controlling the RF unit, wherein the
processor controls the RF unit to transmit control information on
transmission of the CSI to a user equipment (UE) and to receive the CSI
combination from the UE in a subframe to which the CSI combination has
been allocated based on the control information, wherein the CSI
combination comprises different CSIs, wherein the control information
includes information on a maximum payload size of a CSI being able to be
transmitted in one subframe, a transmission period and a transmission
start time point of the CSI combination, and a transmission period and a
transmission start time point of each of the different CSIs.

[0025] Preferably, the transmission period of the CSI combination or each
of the different CSIs is set to a multiple of a predetermined unit
transmission period.

[0026] Preferably, the CSI combination comprises at least two different
CSIs.

[0027] It is to be understood that both the foregoing general description
and the following detailed description of the present invention are
exemplary and explanatory and are intended to provide further explanation
of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and constitute a
part of this application, illustrate embodiment(s) of the invention and
together with the description serve to explain the principle of the
invention. In the drawings:

[0029] FIG. 1 is a diagram showing an example of a radio frame structure
used in a wireless communication system;

[0030]FIG. 2 is a diagram showing an example of a downlink/uplink (DL/UL)
slot structure in a wireless communication system;

[0031]FIG. 3 is a diagram showing a downlink subframe structure used in a
3GPP LTE(-A) system;

[0032]FIG. 4 is a diagram showing an example of an uplink subframe
structure used in a 3GPP LTE(-A) system;

[0035]FIG. 7 is a diagram briefly showing a feedback operation of channel
state information (CSI) in a wireless communication system which supports
a CoMP scheme;

[0036]FIG. 8 is a diagram showing an example of a single CSI transmission
structure;

[0037]FIG. 9 is a diagram showing an example of a multiple CSI
transmission structure which has combined a single CSI transmission
structure;

[0038]FIG. 10 is a diagram showing an example of a multiple CSI
transmission structure which has combined a single CSI transmission
structure;

[0039]FIG. 11 is a diagram showing an example of a multiple CSI
transmission structure by a combination between CSI transmission
structures illustrated in FIG. 8;

[0040] FIG. 12 is a diagram showing an example of a multiple CSI
transmission structure by a combination between CSI transmission
structures illustrated in FIG. 8;

[0041]FIG. 13 is a diagram showing a modified example of a multiple CSI
transmission structure illustrated in FIG. 12;

[0042] FIG. 14 is a diagram showing an example of adjusting a transmission
cycle of an individual CSI in a multiple CSI transmission structure;

[0043] FIG. 15 is a diagram showing an example of utilizing surplus
resources which may be generated when forming a multiple CSI transmission
structure; and

[0044]FIG. 16 is a block diagram showing a transmitting device and a
receiving device which are configured to perform the exemplary
embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0045] Reference will now be made in detail to the preferred embodiments
of the present invention, examples of which are illustrated in the
accompanying drawings. The detailed description set forth below in
connection with the appended drawings is intended as a description of
exemplary embodiments and is not intended to represent the only
embodiments in which the concepts explained in these embodiments can be
practiced. The detailed description includes details for the purpose of
providing an understanding of the present invention. However, it will be
apparent to those skilled in the art that these teachings may be
implemented and practiced without these specific details.

[0046] The following technique, apparatus and system is applicable to
various wireless multiple access systems. For convenience of description,
assume that the present invention is applied to 3GPP LTE(-A). However,
the technical features of the present invention are not limited thereto.
For example, although the following detailed description is made in
detail on the assumption that a mobile communication system is a 3GPP
LTE(-A) system, it is applicable to other prescribed mobile communication
systems by excluding unique items of the 3GPP LTE(-A) system.

[0047] In some instances, well-known structures and devices are omitted in
order to avoid obscuring the concepts of the present invention and the
important functions of the structures and devices are shown in block
diagram form. The same reference numbers will be used throughout the
drawings to refer to the same or like parts.

[0048] In the present invention, a user equipment (UE) may be fixed or
mobile and include various apparatuses which communicate with a base
station (BS) and transmit and receive user data and/or a variety of
control information. The UE may be referred to as a terminal Equipment, a
mobile station (MS), a mobile terminal (MT), a user terminal (UT), a
subscriber station (SS), a wireless device, a personal digital assistant
(PDA), a wireless modem, a handheld device, etc. In the present
invention, a base station (BS) refers to a fixed station which
communicates with a UE and/or another BS and exchanges a variety of data
and control information. The BS is referred to as an advanced base
station (ABS), a node-B (NB), an evolved-NodeB (eNB), a base transceiver
system (BTS), an access point (AP), a processing server (PS), etc.

[0049] In the present invention, a PDCCH (Physical Downlink Control
CHannel)/PCFICH (Physical Control Format Indicator CHannel)/PHICH
(Physical Hybrid automatic retransmit request Indicator CHannel)/PDSCH
(Physical Downlink Shared CHannel) refers to a set of resource elements
or a set of time-frequency resources carrying DCI (Downlink Control
Information)/CFI (Control Format Indicator)/downlink ACK/NACK
(ACKnowlegement/Negative ACK)/downlink data. In addition, a PUCCH
(Physical Uplink Control CHannel)/PUSCH (Physical Uplink Shared CHannel)
refers to a set of resource elements or a set of time-frequency resources
carrying UCI (Uplink Control Information)/uplink data. In the present
invention, in particular, time-frequency resources or resource elements
(REs) allocated to or belonging to PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH
are referred to as PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH REs or
PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH resources. Accordingly, in the
present invention, transmission of a PUCCH/PUSCH by a UE means that an
uplink control information/uplink data/random access signal is
transmitted on a PUCCH/PUSCH. In the present invention, transmission of a
PDCCH/PCFICH/PHICH/PDSCH by a BS means that downlink data/control
information is transmitted on a PDCCH/PCFICH/PHICH/PDSCH.

[0050] In addition, in the present invention, a CRS (Cell-specific
Reference Signal)/DMRS (Demodulation Reference Signal)/CSI-RS (Channel
State Information Reference Signal) time-frequency resources (or REs)
refer to time-frequency resources (or REs) carrying CRS/DMRS/CSI-RS, REs
allocated to CRS/DMRS/CSI-RS or available REs. A subcarrier including a
CRS/DMRS/CSI-RS RE is referred to as a CRS/DMRS/CSI-RS subcarrier and an
OFDM symbol including a CRS/DMRS/CSI-RS RE is referred to as a
CRS/DMRS/CSI-RS symbol. In addition, in the present invention, SRS
time-frequency resources (or REs) refer to time-frequency resources (or
REs) transmitted from a UE to a BS to carry a sounding reference signal
(SRS) used for measurement of an uplink channel state formed between the
UE and the BS. A reference signal (RS) refers to a predefined signal
known to a UE and a BS and having a special waveform and is referred to
as a pilot signal.

[0051] Meanwhile, in the present invention, a cell refers to a
predetermined geographical region in which a BS, node(s) or antenna
port(s) provide a communication service. Accordingly, in the present
invention, communication with a specific cell may refer to communication
with a BS, node or antenna port for providing a communication service to
the specific cell. In addition, a downlink/uplink signal of a specific
cell refers to a downlink/uplink signal from/to a BS, node or antenna
port for providing a communication service to the specific cell. In
addition, channel state/quality of a specific cell refers to channel
state/quality of a channel or communication link formed between a UE and
a BS, node or antenna port for providing a communication service to the
specific cell.

[0052] FIG. 1 is a diagram showing the structure of a radio frame used in
a wireless communication system. In particular, FIG. 1(a) shows a radio
frame structure used in frequency division duplex (FDD) in 3GPP LTE(-A)
and FIG. 1(b) shows a radio frame structure used in time division duplex
(TDD) in 3GPP LTE(-A).

[0053] Referring to FIG. 1, a radio frame used in 3GPP LTE(-A) has a
length of 10 ms (307200Ts) and includes 10 subframes with the same
size. The 10 subframes of the radio frame may be numbered. Ts
denotes sampling time, and is represented by Ts=1/(2048*15 kHz).
Each of the subframes has a length of 1 ms and includes two slots. The 20
slots of one radio frame may be sequentially numbered from 0 to 19. Each
of the slots has a length of 0.5 ms. A time for transmitting one subframe
is defined as a transmission time interval (TTI). Time resources may be
divided by a radio frame number (or a radio frame index), a subframe
number (or a subframe index), a slot number (or a slot index), etc.

[0054] The radio frame may be differently configured according to duplex
mode. For example, in an FDD mode, since downlink (DL) transmission and
uplink (UL) transmission are divided according to frequency, a radio
frame includes only one of a DL subframe or a UL subframe in a
predetermined frequency band of a predetermined carrier frequency. In a
TDD mode, since downlink (DL) transmission and uplink (UL) transmission
are divided according to time, a radio frame includes both a DL subframe
and a UL subframe in a predetermined frequency band of a predetermined
carrier frequency.

[0055] Table 1 shows a DL-UL configuration of subframes within a radio
frame, in a TDD mode.

[0056] In Table 1, D denotes a DL subframe, U denotes a UL subframe and S
denotes a special subframe. The special subframe includes three fields of
DwPTS (Downlink Pilot TimeSlot), GP (Guard Period) and UpPTS (Uplink
Pilot TimeSlot). DwPTS is a time slot reserved for DL transmission and
UpPTS is a time slot reserved for UL transmission.

[0057]FIG. 2 is a diagram showing an example of a downlink/uplink (DL/UL)
slot structure in a wireless communication system. In particular, FIG. 2
shows the structure of a resource grid of a 3GPP LTE(-A) system. One
resource grid exists per antenna port.

[0058] A slot includes a plurality of orthogonal frequency division
multiplexing (OFDM) symbols in a time domain and includes a plurality of
resource blocks (RBs) in a frequency domain. The OFDM symbol means one
symbol slot. Referring to FIG. 2, a signal transmitted in each slot may
be expressed by a resource grid including
NDL/ULRB*NRBsc subcarriers and NDL/ULsymb
OFDM symbols. NDLRB denotes the number of resource blocks (RBs)
in a DL slot and NULRB denotes the number of RBs in a UL slot.
NDLRB and NULRB depend on a DL transmission bandwidth
and a UL transmission bandwidth. NDLsymb denotes the number of
OFDM symbols in a DL slot, NULsymb denotes the number of OFDM
symbols in a UL slot, and NRBsc denotes the number of
subcarriers configuring one RB.

[0059] An OFDM symbol may be referred to as an OFDM symbol, an SC-FDM
symbol, etc. according to multiple access scheme. The number of OFDM
symbols included in one slot may be variously changed according to
channel bandwidth and CP length. For example, in a normal cyclic prefix
(CP) case, one slot includes seven OFDM symbols. In an extended CP case,
one slot includes six OFDM symbols. Although one slot of a subframe
including seven OFDM symbols is shown in FIG. 2 for convenience of
description, the embodiments of the present invention are similarly
applicable to subframes having a different number of OFDM symbols.
Referring to FIG. 2, each OFDM symbol includes
NDL/ULRB*NRBsc subcarriers in a frequency domain. The
type of the subcarrier may be divided into a data subcarrier for data
transmission, a reference signal subcarrier for reference signal
transmission and a null subcarrier for a guard band and a DC component.
The null subcarrier for the DC component is unused and is mapped to a
carrier frequency f0 in a process of generating an OFDM signal or in
a frequency up-conversion process. The carrier frequency is also called a
center frequency.

[0060] One RB is defined as NDL/ULsymb (e.g., 7) consecutive
OFDM symbols in a time domain and defined as NRBsc (e.g., 12)
consecutive subcarriers in a frequency domain. For reference, resource
including one OFDM symbol and one subcarrier is referred to a resource
element (RE) or tone. Accordingly, one RB includes
NDL/ULsymb*NRBsc REs. Each RE within a resource grid
may be uniquely defined by an index pair (k, 1) within one slot. k is an
index applied from 0 to NDL/ULRB*NRBsc-1 in a
frequency domain, and l is an index from 0 to NDL/ULsymb-1 in a
time domain.

[0061] In one subframe, two RBs respectively located in two slots of the
subframe while occupying the same NRBsc consecutive subcarriers
is referred to as a physical resource block (PRB) pair. Two RBs
configuring a PRB pair have the same PRB number (or the same PRB index).
A VRB is a logical resource allocation unit introduced for resource
allocation. The VRB has the same size as the PRB. The VRB is classified
into a localized VRB and a distributed VRB according to the method of
mapping the PRB to the VRB. Localized VRBs are directly mapped to PRBs
and thus VRB number (VRB index) directly corresponds to PRB number. That
is, nPRB=nVRB. The localized VRBs are numbered from 0 to
NDLVRB-1 and NDLVRB=NDLRB. Accordingly,
according to the localized mapping method, VRBs having the same VRB
number are mapped to RRBs having the same PRB number in a first slot and
a second slot. In contrast, the distributed VRB is mapped to the PRB
through interleaving. Accordingly, the distributed VRBs having the same
VRB number may be mapped to RRBs having different PRB numbers in a first
slot and a second slot. Two PRBs which are respectively located in two
slots of a subframe and have the same VRB number are referred to as a VRB
pair.

[0062]FIG. 3 is a diagram showing a downlink subframe structure used in a
3GPP LTE(-A) system.

[0063] A DL subframe is divided into a control region and a data region in
a time domain. Referring to FIG. 3, a maximum of 3 (or 4) OFDM symbols
located in a front part of a first slot of a subframe correspond to the
control region. Hereinafter, a resource region for PDCCH transmission in
a DL subframe is referred to as a PDCCH region. OFDM symbols other than
the OFDM symbols used in the control region correspond to the data region
to which a physical downlink shared channel (PDSCH) is allocated.
Hereinafter, a resource region available for PDSCH transmission in a DL
subframe is referred to as a PDSCH region. Examples of a DL control
channel used in 3GPP LTE include PCFICH (Physical Control Format
Indicator Channel), PDCCH (Physical Downlink Control Channel), PHICH
(Physical hybrid ARQ indicator Channel), etc. The PCFICH is transmitted
in a first OFDM symbol of a subframe and carries information about the
number of OFDM symbols used for transmission of a control channel within
a subframe. The PHICH carries a HARQ ACK/NACK
(acknowledgment/negative-acknowledgment) as a response to UL
transmission.

[0064] Control transmitted via a PDCCH is referred to as downlink control
information (DCI). The DCI includes resource allocation information of a
UE or a UE group and other control information. For example, the DCI
includes transmission format and resource allocation information of a DL
shared channel (DL-SCH), transmission format and resource allocation
information of a UL shared channel (UL-SCH), paging information on a
paging channel (PCH), system information on a DL-SCH, resource allocation
information of a higher-layer control message such as a random access
response transmitted on a PDSCH, a Tx power control command set of
individual UEs in a UE group, a Tx power control command, activation
indication information of voice over IP (VoIP), etc. The size and usage
of the DCI carried by one PDCCH may be changed according to DCI format
and the size of the DCI may be changed according to coding rate.

[0065] A plurality of PDCCHs may be transmitted in a PDCCH region of a DL
subframe. A UE may monitor a plurality of PDCCHs. A BS decides a DCI
format according to DCI to be transmitted to a UE and attaches a cyclic
redundancy check (CRC) to the DCI. The CRC is masked with an identifier
(e.g., a Radio Network Temporary Identifier (RNTI)) according to an owner
or usage of the PDCCH. If the PDCCH is for a specific terminal, a
cell-RNTI (C-RNTI) of the terminal may be masked to the CRC.
Alternatively, if the PDCCH is for a paging message, a paging indicator
identifier (P-RNTI) may be masked to the CRC. If the PDCCH is for system
information (more specifically, a system information block (SIB)), a
system information identifier and a system information RNTI (SI-RNTI) may
be masked to the CRC. If the PDCCH is for a random access response, a
random access-RNTI (RA-RNTI) may be masked to the CRC. CRC masking (or
scrambling) includes an XOR operation of a CRC and an RNTI at a bit
level, for example.

[0066] A PDCCH is transmitted on one control channel element (CCE) or an
aggregate of a plurality of consecutive CCEs. The CCE is a logical
allocation unit used to provide a coding rate to a PDCCH based on a radio
channel state. The CCE corresponds to a plurality of resource element
groups (REGs). For example, one CCE corresponds to nine REGs and one REG
corresponds to four REs. Four QPSK symbols are mapped to each REG. An RE
occupied by an RS is not included in an REG. Accordingly, the number of
REGs within a given OFDM symbol is changed according to presence/absence
of an RS. The REG concept is also used for other DL control channels
(that is, a PCFICH and a PHICH). A DCI format and the number of DCI bits
are determined according to the number of CCEs.

[0067] CCEs are numbered and consecutively used and, in order to simplify
decoding, a PDCCH having a format composed of n CCEs may start from only
a CCE having a number corresponding to a multiple of n. The number of
CCEs used to transmit a specific PDCCH, that is, a CCE aggregation level,
is determined by a BS according to a channel state. For example, in case
of a PDCCH for a UE having a good DL channel (e.g., a UE adjacent to a
BS), one CCE may be sufficient. However, in case of a PDCCH for a UE
having a bad channel (e.g., a UE located at a cell edge), 8 CCEs are
required to obtain sufficient robustness.

[0068]FIG. 4 is a diagram showing an example of an uplink subframe
structure used in a 3GPP LTE(-A) system.

[0069] Referring to FIG. 4, a UL subframe may be divided into a control
region and a data region in a frequency domain. One or several physical
uplink control channels (PUCCHs) may be allocated to the control region
in order to carry uplink control information (UCI). One or several
physical uplink shared channels (PUSCHs) may be allocated to the data
region of the UL subframe in order to carry user data. The control region
and the data region in the UL subframe are also referred to as a PUCCH
region and a PUSCH region, respectively. A sounding reference signal
(SRS) may be allocated to the data region. The SRS is transmitted on a
last OFDM symbol of a UL subframe in a time domain and is transmitted on
a data transmission band, that is, a data region, of the UL subframe.
SRSs of several UEs, which are transmitted/received on the last OFDM
symbol of the same subframe, are distinguished according to frequency
location/sequence.

[0070] If a UE employs an SC-FDMA scheme in UL transmission, in order to
maintain a single carrier property, in a 3GPP LTE release-8 or release-9
system, a PUCCH and a PUSCH may not be simultaneously transmitted on one
carrier. In a 3GPP LTE release-10 system, support of simultaneous
transmission of a PUCCH and a PUSCH may be indicated by a higher layer.

[0071] In a UL subframe, subcarriers distant from a direct current (DC)
subcarrier are used as the control region. In other words, subcarriers
located at both ends of a UL transmission bandwidth are used to transmit
uplink control information. A DC subcarrier is a component which is not
used to transmit a signal and is mapped to a carrier frequency f0 in
a frequency up-conversion process. A PUCCH for one UE is allocated to an
RB pair belonging to resources operating in one carrier frequency and RBs
belonging to the RB pair occupy different subcarriers in two slots. The
allocated PUCCH is expressed by frequency hopping of the RB pair
allocated to the PUCCH at a slot boundary. If frequency hopping is not
applied, the RB pair occupies the same subcarrier.

[0072] The size and usage of UCI carried by one PUCCH may be changed
according to PUCCH format and the size of the UCI may be changed
according to a coding rate. For example, the following PUCCH format may
be defined.

[0073] Referring to Table 2, PUCCH format 1 series and PUCCH format 3
series are used to transmit ACK/NACK information and PUCCH format 2
series are mainly used to carry channel state information such as CQI
(channel quality indicator)/PMI (precoding matrix index)/RI (rank index).

[0074]FIG. 5 illustrates a PUCCH-based periodic channel state information
(CSI) transmission structure defined in LTE release 8. In FIG. 5, the
mode 1-CSI transmission structure indicates a case in which wideband PMI
and CQI are transmitted along with RI, and the mode 2-CSI structure
indicates a case in which wideband PMI and CQI, and sub-band CQI are
transmitted along with the RI.

[0075]FIG. 6 illustrates a PUCCH-based periodic CSI transmission
structure additionally defined in LTE release 10. In LTE release 10, the
CSI transmission structure may support transmitting antennas up to 8
transmitting antennas. Here, the PMI has been changed into the first PMI
(1st PMI) for the average channel direction and the second PMI (2nd PMI)
for the instantaneous channel direction, and the precoding type indicator
(PTI) for whether to transmit the sub-band channel information has been
added.

[0076] The first, second and third CSI transmission structures of FIG. 6
indicate a case of transmitting a wideband CSI, and are distinguished in
that, among wideband CSIs, the 1st PMI may be transmitted along with the
RI, may be transmitted along with the CQI, or may be transmitted through
other resources. The last transmission structure indicates a case in
which the subband CSI is transmitted.

[0077]FIG. 7 briefly illustrates a feedback operation of channel state
information in a wireless communication system which supports a CoMP
scheme.

[0078] The present invention suggests a multiple CSI transmission
structure for reflecting each of characteristic of channels between a UE
and transmission points (TPs) and transmitting multiple CSIs through the
extended container when CSI for part or all of the TPs within the
coordinated multiple point transmission and reception (COMP) group is
required in the downlink of the multiple cell wireless communication
system.

[0079] In the present specification, a container may generally refer to
time-frequency resources for transmitting the CSI. As another example,
the container may refer to a PUCCH for transmitting for the CSI. As
further another example, the container may refer to a PUSCH for
transmitting the CSI. Further, an extended container is a combination of
at least two of the containers, and is the extended concept of
time-frequency resources in the time-frequency resources for the existing
general CSI transmission. For example, if one CSI (i.e., any one of CQI,
PMI, PTI and RI) has been transmitted through the one container before,
at least two CSIs may be simultaneously transmitted through the extended
container.

[0080] Hereinafter, in the present specification, the exemplary
embodiments of the present invention will be explained based on the
container and the extended container, but as explained above, the
container and the extended container may also refer to time-frequency
resources, PUCCH or PUSCH, etc.

[0081] Further, referring to the PUCCH format of Table 2 above, for
example, the concept of the container and the extended container will be
described. If each of the PUCCH formats (1, 1a, 1b, 2, 2a, 2b, 3)
corresponds to the container, at least two combinations of each PUCCH
format may correspond to the extended container.

[0082] Further, the combination of at least two time-frequency resource
structures for such an individual CSI transmission is called a multiple
CSI transmission structure.

[0083] A large number of TPs as well as three TPs (TP1, TP2,
TP3) illustrated in FIG. 7 of the present specification may
participate in the CoMP operation, and a group of the coordinated
multiple transmission and reception (CoMP) including a plurality of TPs
is called a CoMP set. Part or all of the TPs, which belong to the CoMP
set, may participate in the CoMP on the UE according to the channel
state. Here, each TP may include a plurality of antenna ports. Further,
as described above, in the present specification, the TP may be indicated
compatible with the BS.

[0084] In a wireless communication system such as 3GPP LTE, etc., the CSI
transmission structure is supported to improve downlink system
performance. For example, the CSI of LTE release 8 includes channel
information such as the rank indicator (RI), channel quality information
(CQI), the precoding matrix indicator (PMI), etc., and supports two or
four transmitting antennas. Here, the RI is transmitted in a sub-frame
which is distinguished from that of CQI and the PMI, and the CQI and PMI
are configured as values selected under the assumption of the RI. The CSI
may be periodically or non-periodically transmitted.

[0085] In the CoMP group comprised of a plurality of TPs, a plurality of
channels exist between the TPs and UEs, and the CSI on part or all of the
channels may be utilized in the CoMP scheme. Hence, the CSI for the CoMP
set should be able to include a single set of or a plurality of sets of
channel information. The method of transmitting CSI on the CoMP set may
exist in various forms. For example, if there is an individual uplink
channel for CSI transmission between UEs and each of the TPs, the CSI for
each TP may be directly transmitted through the individual uplink
channel. However, individual CSI transmission for each TP may become
impossible, and in such a case, multiple CSIs may be transmitted to TPs
corresponding to each CSI through the backhaul network after transmitted
to a specific TP. FIG. 7 shows a case (option 1) in which, in a CoMP set
comprised of TP1, TP2 and TP3, if the UE transmits the CSI
for each of TPs using an individual channel, and a case (option 2) in
which the UE transmits all CSIs to a specific TP (i.e., TP1), and
then the TP transmits the CSI for each TP (i.e., TP2, TP3) to
each TP through the backhaul network.

[0086] Among the above suggested CSI transmission methods, option 1 may be
applied without separately changing the existing single CSI transmission
structure when transmitting the CSI to each TP, but in the case of option
2, a multiple CSI transmission structure in which the UE can transmit a
plurality of CSIs to a specific TP. Here, the extended CSI container may
be considered in the multiple CSI transmission structure, and for
example, PUCCH format 3 suggested in LTE release 10 may be utilized.
Here, the extended CSI container-based multiple CSI transmission
structure should be able to reflect the CSI transmission structure which
is suitable for each CSI. Different CSI transmission structures may be
applied to each CSI according to the channel environment. For example, in
FIG. 7, the CSI transmission structure of FIG. 5, which supports four
transmitting antennas, may be appropriate for TP1 and TP2, but
the CSI transmission structure of FIG. 6, which supports 8 transmitting
antennas, may be appropriate for TP3. Hence, the multiple CSI
transmission structure should be designed to reflect the CSI transmission
structure, which is appropriate for each CSI, as much as possible, by
utilizing the extended CSI container.

[0087]FIG. 8 illustrates an example of the entire CSI transmission
structure. Among PUCCH-based CSI transmission structures suggested in LTE
release 8 and release 10, the entire CSI transmission structures may be
broadly classified into two cases illustrated in FIG. 8 except the case
in which the 1st PMI is transmitted in independent resources.

[0088] Container A includes an RI, PTI, 1st PMI, etc., container B
includes a wideband PMI or CQI, and container C may include subband PMI
or CQI. The CSI according to such container types (A, B or C) is merely
an example, and does not limit the scope of rights of the present
invention. In the present invention, suggested is a method for
configuring the number of extended containers and the maximum payload
size of the extended containers for the multiple CSI transmission
structure, and combining the extended containers with containers within
several single CSI transmission structures.

[0089] It is assumed that a multiple CSI transmission structure is formed
by combining the same two CSI transmission structures corresponding to
Type1 defined in FIG. 8. Here, if it is assumed that the number of
the extended containers is two (2), and only 2 containers may be combined
with each extended container maximally in consideration of the payload,
possible CSI combinations are shown in FIG. 9.

[0090] As another example, when a multiple transmission structure is made
by combining the same CSI transmission structure corresponding to
Type2 defined in FIG. 8, it is assumed that respectively two kinds
of containers may be combined in three extended containers. Here, the
types of extended containers, which may be generated, are shown in FIG.
10.

[0091] Additionally, when two different CSI transmission structures
corresponding to Type1 and Type2 defined in FIG. 8 are
combined, three extended containers for respectively containing maximum
two containers are assumed as shown in FIG. 10, possible extended
container types may be expressed in a form that excludes the sub-band
CSI-related container C (i.e., SB1 at each case) from one side CSI
transmission structure. Hereinafter, for the convenience of explanation,
the operation of the present invention will be described for a few
extended container types on the basis of the transmission period.

[0092]FIG. 11 illustrates a multiple CSI transmission structure which is
applicable in the case in which CSI transmission structures of Type1
are combined or CSI transmission structures of Type2 are combined,
and here CSI1 and CSI2 refer to channel information for
TP1 and TP2, respectively.

[0093] FIG. 12 shows a multiple CSI transmission structure which is
applicable in the case in which the CSI transmission structure of
Type1 is combined with the CSI transmission structure of Type2.
The case, in which different CSI transmission structures are combined,
may be considered in terms of Type1 and Type2. Here, extended
container A follows a form in which several container As are combined as
shown in FIG. 11. Further, in consideration of transmission period,
extended container B may include container Bs of both Type1 and
Type2 or only container B of Type2. Here, in the former case,
the extended container C includes only container C of Type2, and in
the latter case, the extended container C includes both container B of
Type1 and container C of Type2.

[0094] If the extended container may contain three containers maximally in
FIG. 12, a multiple CSI transmission structure may be constituted by
setting two extended containers. For example, in Type1-2,b of the
above example, the wideband CSI for CSI2 is not transmitted in a
separate extended container, and may be transmitted in extended container
A where the RI is transmitted. Specifically, the multiple CSI
transmission structure may be supported with a total of two extended
containers by allocating the RI of CSI1, the RI of CSI2, and
the wideband CSI to one extended container, and allocating the subband
CSI of CSI1 and the subband CSI of CSI2 to another extended
container. FIG. 13 illustrates this example.

[0095] FIG. 14 illustrates an example of adjusting a transmission period
of an individual CSI in a multiple CSI transmission structure. When a
plurality of CSI transmission structures are combined, the transmission
period, which is appropriate for each CSI transmission structure, may be
different, or a case, in which the period should be adjusted according to
a need, may occur. In the present invention, an offset of the
transmission time point (or transmission start time point) and the
transmission period for an individual CSI within the extended container
of the multiple CSI transmission structure are configured to be
adjustable in consideration of the above environment. Preferably, the
transmission period may be adjusted within a range in which the cycle is
a multiple of a predetermined unit transmission period.

[0096] For example, when considering a multiple CSI transmission structure
in which the same two single CSI transmission structures are combined
from the perspective of Type1 defined in FIG. 8, the transmission
start time point of CSI1 and CSI2 may be set, and/or the period
(N1, N2) for each of CSI1 and CSI2 may be set. The
suggested method is applicable with the same principle even in the case
in which different CSI transmission structures are combined (e.g.,
Type1-2).

[0097] In another exemplary embodiment of the present invention, the
offset of transmission time point and the transmission period for each
extended container are set to be adjustable by extending a scheme for
adjusting the offset of transmission time point and the transmission
period for each container (i.e., for each CSI) in the existing single CSI
transmission structure. Here, the transmission period for each of the
extended containers may be determined as a multiple of a predetermined
unit transmission period, or may be set to be shorter or longer than the
unit transmission period.

[0098] Further, in order to allocate resources for each of the extended
containers, a basic offset of the transmission time point is allowed to
be set by the upper layer signal, and if at least two extended containers
are allocated to time-frequency resources and collide each other, the
extended container with a higher priority may be transmitted among
predefined extended containers, or extended containers of a new form,
which have a recombination of single CSIs, may be transmitted by
recombining several single CSIs contained in the predefined extended
containers which collide each other.

[0099] A method of setting the priority for the CSI transmission when a
plurality of CSI transmission structures is simultaneously applied will
be described below. As an example of an extended container in an LTE
system according to another exemplary embodiment of the present
invention, PUCCH format 3 suggested in LTE release 10 may be considered,
but a situation, in which multiple CSIs required in the CoMP scheme
cannot be contained PUCCH format 3, may occur. In such a situation, there
is a need for operating a new CSI transmission structure separately from
the multiple CSI transmission structure. The new CSI transmission
structure may be the existing CSI transmission structure for a single TP,
or may be a separate multiple CSI transmission structure. In the present
invention, when the independent CSI transmission structure is
simultaneously applied, a CSI preferred at the time of a collision of
resources with each other may be protected by giving the priority. At
this time, the priority may be given in the unit of the CSI transmission
structure, or may be given for each CSI. Further, the priority may be
given according to the types of the extended containers (A, B or C).

[0100] FIG. 15 illustrates a method for utilizing surplus resources, which
are generated in forming the multiple CSI structure, as resources for
transmitting additional information which is appropriate for the CoMP
scheme. Here, the surplus resources mean empty resources, which are not
allocated any CSIs, within the extended container when the extended
container is considered as the time-frequency resources, and in another
expression, the surplus resources may also mean resources which can
include a container which is additionally allocated within the extended
container.

[0101] When transmitting a combined CSI in the extended container, surplus
resources may be generated within the extended container depending on the
situation. For example, in the case in which different CSI transmission
structures of Type1 and Type2 defined in FIG. 8 are combined,
surplus resources may be generated inside the extended container at a
specific transmission time point as shown in FIG. 12 (extended container
C in Type1-2,a, and extended container B in Type1-2,b). The
surplus resources may also be generated in the case in which each CSI
transmission period may be adjusted for the combined CSI as shown in FIG.
14 (extended container B of Type1-1).

[0102] According to another exemplary embodiment of the present invention,
a method for utilizing the surplus resources as resources for
transmitting additional information, which is appropriate for the CoMP
scheme, is suggested. For example, if it is assumed that the joint
transmission (JT) scheme has been applied, inter point CSIs such as a
phase difference or a channel size difference between TPs, which
participate in the JP scheme, may be required to enhance performance of
the CoMP scheme, and the inter point CSIs may be transmitted through the
surplus resources. Here, the inter point CSI may be determined based on
CSIs which are available at the transmission time point.

[0103] As another application, in order to support the coordinated
scheduling (CS) or coordinate beamforming (CB) scheme, information on
whether resources may be emptied at a specific band or coordinated
beamforming may be supported may transmitted through surplus resources,
or in order to support a dynamic point selection (DPS), information on
from which TP each CSI is transmitted may be transmitted through surplus
resources. However, additional information does not necessarily need to
be transmitted in the surplus resources, and if there is no information
to be transmitted to the surplus resources, the payload of the extended
container may be set to be small while the transmission power may be
increased.

[0104] According to the exemplary embodiment shown in FIG. 15, additional
information as well as CSI may be transmitted through surplus resources
which may be generated when forming a multiple CSI transmission
structure.

[0105]FIG. 16 is a block diagram illustrating components of a
transmitting device 10 and a receiving device 20 which perform the
present invention.

[0106] The transmitting device 10 and the receiving device 20 include a
radio frequency (RF) unit 13 and 23 for transmitting or receiving radio
signals which carry information and/or data, a signal, a message, etc., a
memory 12 and 22 for storing various sets of information related with
communication within a wireless communication system, and a processor 11
and 21 which is functionally connected to the components such as the RF
unit 13 and 23 and the memory 12 and 22, and is configured to control the
memory 12 and 22 and/or the RF unit 13 and 23 so that the device performs
at least one of the exemplary embodiments of the present invention.

[0107] The memory 12 and 22 may include a program for processing and
control of the processor 11 and 21, and may temporarily store
input/output information. The memory 12 and 22 may also be utilized as a
buffer.

[0108] The processor 11 and 21 generally controls overall operation of
various modules within the transmitting device or the receiving device.
In particular, the processor 11 and 21 may perform various control
functions for performing the present invention. The processor 11 and 21
may also be called a controller, a microcontroller, a microprocessor, a
microcomputer, etc. The processor 11 and 21 may be implemented by
hardware, firmware, software and a combination thereof. In the case in
which the present invention is implemented by hardware, application
specific integrated circuits (ASICs), digital signal processors (DSPs),
digital signal processing devices (DSPDs), programmable logic devices
(PLDs), field programmable gate arrays (FPGAs), etc., which are
configured to perform the present invention, may be included in the
processor 11 and 21. Further, in the case in which the present invention
is implemented using firmware or software, the firmware or software may
be configured to include modules, procedures, functions, etc. for
performing functions and operations of the present invention, the
firmware or software, which is configured to perform the present
invention, may be included in the processor 11 and 21, or may be stored
in the memory 12 and 22 and operated by the processor 11 and 21.

[0109] The processor 11 of the transmitting device 10 codes and modulates
a signal, which is scheduled from the processor 11 or a scheduler
connected to the processor 11, and is to be transmitted to the outside,
and transmits the coded and modulated signal to the RF unit 13. For
example, the processor 11 converts a data array to be transmitted into K
layers by de-multiplexing, channel-coding, scrambling, and modulating the
data array. The coded data array may also be called a codeword, and is an
equivalent of a transmission block which is a data block provided by a
medium access control (MAC) layer. One transport block (TB) is coded as
one codeword, and each codeword is transmitted to the receiving device in
the form of one or more layers. The RF unit 13 may include an oscillator
for frequency up conversion. The RF unit 13 may include Nt transmission
antennas (Nt is a positive integer).

[0110] The signal processing process of the receiving device 20 is
constituted in a manner that is opposite to the signal processing process
of the transmitting device 10. Under the control of the processor 21, the
RF unit 23 of the receiving device 20 receives radio signals transmitted
by the transmitting device 10. The RF unit 23 may include Nr receiving
antennas (here, Nr is a positive integer), and the RF unit 23
frequency-down-converts each of the signals received through the
receiving antennas, thereby restoring the signals as baseband signals.
The RF unit 23 may include an oscillator for frequency down conversion.
The processor 21 may restore data, which was intended to be transmitted
by the transmitting device 10, by decoding and demodulating radio signals
received through the receiving antenna.

[0111] According to an exemplary embodiment of the present invention, the
RF unit 13 and 23 includes at least one antenna. The antenna may transmit
a signal processed by the RF unit 13 and 23 to the outside or may receive
a radio signal from the outside and transmit the received signal to the
RF unit 13 and 23. The antenna is also call an antenna port. Each antenna
may correspond to one physical antenna, or may be constituted by a
combination of one or more physical antenna elements. The signal
transmitted from each antenna may not be further decomposed by the
receiving device 20. Reference signals (RS) transmitted in response to
the antenna define an antenna viewed from the perspective of the
receiving device 20, and allows the receiving device 20 to perform
channel estimation on the antenna regardless of whether the channel is a
signal radio channel from one physical antenna or is a composite channel
from a plurality of physical antenna elements. That is, the antenna is
defined so that the channel, on which the symbol on the antenna is
transmitted, may be drawn from the channel on which another symbol of the
same antenna is transmitted. The RF unit, which supports a multi-input
multi-output (MIMO) function that transmits and receives data using
multiple antennas, may be connected to two or more antennas.

[0112] In the exemplary embodiments of the present invention, the UE or
relay is operated as a transmitting device 10 in uplink and as a
receiving device 20 in downlink. In the exemplary embodiments of the
present invention, the BS is operated as a receiving device 20 in uplink
and as a transmitting device 10 in downlink.

[0113] Hereinafter, a processor, a memory and a RF unit, which are
included in the base station (BS), are called a BS processor, a BS memory
and a BS RF unit, respectively. Further, a processor, a memory and a RF
unit, which are included in the UE, are called a UE processor, a UE
memory and a UE RF unit, respectively. In the present invention, the BS
processor may be a processor located in the BS, or may be a BS controller
which is connected to the BSE through a cable or a dedicated line and is
configured to control the BS.

[0114] Hereinafter, the invention will be described on the basis of the
downlink, and thus the transmitting device 10 corresponds to the BS and
the receiving device 20 corresponds to the UE. The receiving device 20
may correspond to the UE configured to transmit channel state information
in a wirless communication system. The receiving device 20 may include a
radio frequency (RF) unit 23 configured to transmit or receive radio
signals and a processor 21 configured to control the RF unit. Further,
the receiving device 20 may include a memory 22 configured to store a
series of data including information needed for performing communication
with the BS.

[0115] The UE processor 21 may control the UE RF unit 23 to receive
control information about a transmission of the CSI from a serving eNodeB
(base station). The UE processor may be configured to allocate the CSI
combination comprised of different CSIs to one subframe on the basis of
the received control information. Further, the UE processor may control
the UE RF unit to transmit the CSI combination in the allocated subframe
to the serving eNodeB. Here, the control information may include
information on a maximum payload size of a CSI being able to be
transmitted in one subframe, the transmission period and the transmission
start point of the CSI combination or each of the different CSIs. As
such, the UE processor may adjust the transmission period and the
transmission start point of the CSI combination, or adjust the
transmission period and the transmission start point of each of the
different CSIs when allocating the CSIs or the CSI combination to the
subframe. Here, the CSI combination may be comprised of at least two
different CSIs.

[0116] Further, the transmission period of the CSI combination or each of
the different CSIs may be set to a multiple of a predetermined unit
transmission period. In the case in which the CSI may be additionally
allocated to the subframe to which the CSI combination has been
allocated, the UE processor may be configured to additionally allocate
the additional CSI to the subframe. Here, the additional CSI may include
CSI between base stations which perform downlink transmission to the UE
(that is, inter point CSI).

[0117] The UE processor may be configured to allocate the combination of
different types of CSIs to one subframe. In other words, at least two
sets of information among RI, PMI, 1st PMI, wideband PMI/CQI, and
subband PMI/CQI may be allocated to one subframe. Further, the CSI for
different base stations/TPs may be allocated to one subframe. This means
that at least two CSIs may be simultaneously transmitted, and the CSIs
for different base stations or TPs may be simultaneously transmitted.

[0118] Likewise, the CSI feedback on the CoMP set of the UE may be
smoothly performed by configuring a multiple CSI transmission structure.
In particular, a more efficient time-frequency resource allocation for
the CSI can be performed by adjusting the transmission period and the
transmission start time point of the extended container or an individual
CSI.

[0119] When at least two CSI combinations are allocated to one subframe
and collide with each other, the UE processor may be configured to
control the UE RF unit to transmit one CSI combination selected from at
least two CSI combinations. The selection is determined according to the
order or priority, and the priority may be given to each CSI combination
or each CSI. The stability of the wireless communication system, to which
the present invention is applied, may be secured by making more important
CSI information (or CSI information of a high priority) transmitted to
the base station in preparation of the collision between CSI
combinations.

[0120] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention without
departing from the spirit or scope of the inventions. Thus, it is
intended that the present invention covers the modifications and
variations of this invention provided they come within the scope of the
appended claims and their equivalents.

INDUSTRIAL APPLICABILITY

[0121] The exemplary embodiments of the present invention may be utilized
in a user equipment, a base station and other devices in a wireless
communication system.